Emerging Advances in Photothermal Materials for Water Purification

Dear Colleagues,

It is well known that 70% of the earth's surface is covered by water, while only about 3% of water is fresh and drinkable. The shortage of freshwater resources has become one of the greatest threats to the sustained growth of the world economy, which is exacerbated by environmental pollution, population growth, and socio-economic development. In addition to improving the utilization of existing freshwater resources, seawater desalination and sewage treatment and reuse are considered key means to alleviate the current water shortage situation. In recent years, using solar energy to drive evaporation to produce fresh water has become one of the most promising new photothermal technologies. Solar energy could enable eco-friendly, low-cost, electricity-independent, and decentralized water purification, which would be very important for developing regions suffering from a shortage of clean water, as well as for urban communities in emergency situations.

The past decade has witnessed the rise of photothermal materials designed for solar-driven water evaporation at the air-water interface for water purification. As such, efforts have been made to find optimal materials with excellent photothermal conversion and heat localization functions, such as nanostructured carbon, plasmonic metals, conductive polymers, hydrogels, and semiconductors. Photothermal materials for efficient solar-to-vapour conversion can be optimized through an isolated evaporating surface, rational architecture of water replenishment, appropriate surface wettability, topographic design, etc. Various underlying mechanisms, such as heat concentration, interfacial evaporation, the enlargement of the effective evaporating area, and water activation, are also important. Despite remarkable developments in photothermal materials and solar-driven water evaporation, more fundamental studies are needed to fully elucidate the interaction between water and functional materials and its influence on water evaporation.

Here, we consider new opportunities and approaches for the application of photothermal materials to enhance the efficiency and affordability of water purification using solar-driven interfacial evaporation technologies.

In this Special Issue, in addition to the photothermal conversion processes of various solar absorber materials and the conceptual designs of different interfacial photothermal evaporation, we welcome papers that focus on nanostructured and microstructured materials in both fundamental research and practical water purification applications.

We are pleased to invite you to submit a manuscript to this Special Issue. Regular articles, communications, and reviews are all welcome.

We look forward to receiving your contributions.

Dr. Xiaohu Ren
Guest Editor

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• photothermal conversion
• interfacial water evaporation
• solar-driven steam generation
• desalination
• water purification
• nanomaterials
• wastewater treatment
• structure development
• heat conduction